1. Field of the Invention
The present invention relates to an improvement in high production sheeting devices for comestible products (e.g., tortillas and tortilla chips). More specifically, the invention relates to a control system which continuously monitors the thickness of a rolled sheet of the comestible product and automatically adjusts the sheeting device to maintain the rolled product sheet at a desired preset thickness.
2. Description of Related Art
Corn tortillas and tortilla chips are cut from a sheet of corn dough, called "masa," and then baked and/or fried. In mass production, the sheeting and cutting stages are accomplished by a tortilla sheerer.
High production tortilla sheerers feed masa from a hopper between a pair of large, stainless steel rollers which roll the masa into a sheet of substantially uniform thickness. The rollers are spaced apart in production to form a gap, known as a "pinch point gap," through which the masa passes. The masa adheres to the surface of one of the rollers, known as the exit roller, after passing through the pinch point gap. A third roller then cuts the masa into either tortillas or tortilla chips. The third roller, known as the cutting roller, commonly has either circular shaped (for tortillas) or triangular-shaped (for tortilla chips) cutting guides positioned on the cylindrical external surface of the cutting roller. The cut tortillas or chips then are stripped from the exit roller by a wire and/or a blower, or by a similar device.
High production tortilla sheerers automate virtually every step of the sheeting and cutting process. One challenge that remains, however, is to accurately control the thickness of the masa sheet before cutting.
The consistency of corn masa commonly varies over time depending upon humidity, temperatures, and other known factors, and occasionally will contain hard kernels of corn. If the distance between the sheeting rollers is rigidly fixed, the thickness of the exiting masa sheet typically depends on the masa consistency. The consistency of the masa can also vary within the hopper, and, thus, vary across the length of the sheeting rollers. As a result, the thickness of produced tortillas or chips varies.
Prior sheeting rollers commonly include adjustment screws to move the rollers relative to each other. The gap between the rollers thus can be adjusted by an operator of the tortilla sheerer.
In high speed production, a worker, at intervals, commonly measures the thickness of the exiting masa sheet or weighs the exiting masa sheet, and then adjusts the gap between the sheeting rollers, as necessary, using the adjustment screws. This human oversight increases cost and slows production. In addition, human intervention often leads to errors in production, which in turn results in waste and in an inconsistent product.